Enhanced arsenic removal from groundwater using synthesized TiO 2 -PAN composite bead

A bead-type TiO2–polyacrylonitrile composite (TiO2–PAN beads) was successfully synthesized via a single-step phase-inversion/sol – gel method, creating structurally robust beads with uniformly immobilized anatase crystallites. This composite effectively removed both arsenite As(III) and arsenate As(V) from water under neutral pH conditions without the need for arsenite pre-oxidation. Batch adsorption tests yielded monolayer capacities of 63.3 mg g−1 for As(III) and 43.9 mg g−1 for As(V), with pseudo-second-order kinetics and activation energies (23–62 kJ mol−1) indicative of chemisorption. Adsorption efficiencies remained above 90% across pH 4–8 and were resistant to common groundwater anions, except phosphate. Thermodynamic analyses revealed an endothermic and spontaneous adsorption driven by inner-sphere complexation. In fixed-bed column tests (flow velocity 1.8 m h−1), breakthrough capacities reached 16.1 mg g−1 for As(III) and 10.9 mg g−1 for As(V), accurately modeled by the Bohart – Adams equation. Importantly, the beads maintained structural integrity and consistent adsorption performance through multiple regeneration cycles. Overall, the TiO2–PAN composite offers a scalable, regenerable, and practical solution for simultaneous arsenic remediation in decentralized drinking water systems.